This invention generally relates to vacuum processing systems. Specifically, this invention relates to methods and apparatuses for manufacturing components using a vacuum processing system having an improved transfer chamber.
A number of benefits can be obtained by manufacturing certain functional components within a vacuum environment. In view of these advantages, vacuum processing systems for the processing of various substrates have been developed. Typically, a vacuum processing system has a centralized transfer chamber mounted on a monolith platform. The transfer chamber is the center of activity for the movement of the substrate being processed in the system. Substrates are generally in the transfer chamber only long enough to be transferred to another chamber for storing or processing. One or more process chambers attach to the transfer chamber at valves through which substrates are passed by a robot in the transfer chamber. The valves close in order to isolate the process chambers while substrates are being processed therein.
Physically, the process chambers are either supported by the transfer chamber and its platform or are supported on their own platform. Inside the system, the transfer chamber is typically held at a constant vacuum, whereas, the process chambers may be pumped to a greater vacuum for performing their respective processes. Following processing, the pressure of the process chamber must be returned to the level in the transfer chamber before opening the valve to permit access between the chambers.
Access to the transfer chamber for substrates from the exterior of the system, or from the manufacturing facility, is typically through one or more load lock chambers. The load lock chambers cycle between the pressure level of the ambient environment and the pressure level in the transfer chamber in order for the substrates to be passed, so the load lock chambers transition the substrates between the atmospheric pressure of a very clean environment to the vacuum of the transfer chamber.
Some common transfer chambers have facets for four to six process chambers and load lock chambers. For a six-faceted transfer chamber, typically two of the facets are for load lock chambers, and the other four facets are for process chambers. The process chambers include rapid thermal processing (RTP) chambers, physical vapor deposition (PVD) chambers, chemical vapor deposition (CVD) chambers, etch chambers, etc. The productivity of a vacuum processing system is increased when more process chambers are mounted to the transfer chamber, because more substrates can be processed at a given time. Additionally, less space is required in the manufacturing facility if the productivity of the system is maximized. Thus, there is a need for larger transfer chamber to allow the mounting of a greater number of process chambers.
In addition, certain substrates to be processed are very large, and thus require a large transfer chamber to allow processing of the substrate. For example, glass plates of certain flat-panel plasma displays are processed using thin-film techniques to deposit horizontal electrodes and vertical column electrodes onto the glass. Since it is desirable to process very large plates of glass for this purpose, a very large transfer chamber is necessary to manipulate the glass substrate for transfer to a processing unit.
It is desirable to keep the volume of the larger transfer chamber to a minimum in order to decrease manufacturing costs, increase efficiency of the chamber, and to reduce the effects of contamination due to microparticulate matter within the chamber. There is thus a need in the art for a vacuum processing system with improved capacity and efficiency for high throughput production of processed substrates.
The present invention features a vacuum processing system having a domed lid on at least the transfer chamber of the system. This domed lid can be used with any vacuum processing system that utilizes a circular lid to form an airtight seal between the edge of the lid and the corresponding edge of the chamber. Moreover, a single domed lid can be designed for attachment in either a convex or a concave configuration, allowing the user to change configuration if desired for different processing protocols.
The lid of the invention is more cost effective and can be of greater diameter than conventional transfer chamber lids due to the decreased weight of the domed lid compared to conventional, flat lids. These lids may be in any desired size range, and preferably are in a size range up to about 100 inches in diameter. The domed lid can be constructed using any number of methods known in the art such as hydroforming, electroplating, and the like. In a preferred embodiment, the lid is produced through spinning a metal, and in particular spinning stainless steel.
In a preferred embodiment, the lid is comprised of one or more windows or access features to allow a user or a diagnostic device to view the substrate in the chamber during the manufacturing process, e.g., to monitor positioning of the substrate prior to entrance into a processing chamber. A window for visualization of the substrate may be a side window, i.e. a window that runs circumferentially at the edge of the transfer chamber lid, or a window in the dome portion of the lid.
It is thus a feature of the invention that the domed transfer chamber lid may be provided with windows or other means for visualization of the substrate.
A single manufactured lid can be provided either convex or concave to the chamber, thus providing flexibility to the user to alter the configuration of the lid. This is enabled in part by a structural feature that functions to prevent lifting of the lid from the o-ring at the lid attachment site upon introduction of the vacuum to the transfer chamber. In one exemplary embodiment, the structural feature involves the placement of the o-ring relative to the domed lid, i.e. an o-ring further from the edge to better prevent the lifting of the edge of the transfer chamber lid. In a preferred embodiment, a structural feature in the lid itself that absorbs distortion, such as an xe2x80x9cSxe2x80x9d transition as described herein, is added to the structure of the chamber lid to prevent lifting during use. This allows the user to change configuration of the lid depending on the needs of the vacuum processing chamber for different purposes. This flexibility of placement of the domed lid applies to lids with or without a side window.
It is thus another feature of the invention that the domed transfer chamber lid may be attached in either the convex or the concave configuration.
It is an advantage of the present invention that the domed lid can be manufactured using a number of techniques including but not limited to spinning, hydroforming, electroplating, and the like.
It is yet a further advantage of the invention that a single domed lid may be used in either configuration.
It is a further advantage of the invention that the configurations of the domed transfer chamber lid convex to the chamber can decrease the volume of the transfer chamber. Decreased volume can decrease the manufacturing costs as well as decreasing microcontamination.
It is yet a further advantage of the invention that the domed transfer chamber may be greater in diameter than conventional transfer chamber lids, thus providing the capability of processing larger substrates and/or more substrates simultaneously.
It is yet another advantage of the invention that a structural feature that absorbs distortion may be added to prevent lifting of the lid due to vacuum pressure.
These and other objects, advantages, and features of the invention will become apparent to those persons skilled in the art upon reading the details of the vacuum processing system as more fully described below.